B737 First Officer reported prevention of an inadvertent escape slide deployment after a series of delays and maintenance issues during a blizzard. Maintenance was involved and aircraft was eventually refused.

Narrative

ZZZ was IROPS (Irregular Operations) with a Winter Storm Warning and Blizzard conditions. My normal commute time to the airport is 25 minutes. Due to the weather; I left at XA:00 for a XB:15 Report. I parked at the airport at XA:50. Upon arriving at the jet; around XB:15; the boarding area was fairly chaotic with passengers and 20-25 wheelchairs. When I got down the jet bridge; I met the captain and began to discuss the action plan with the weather. I was informed that the Stall Test and Mach test were not testing properly and we needed to clear the flaps being left down to get a new Maintenance Release. I asked the captain if he wanted me to go and have boarding stopped for us to try and build some time; which he agreed. I told the agent in the bridge we had a maintenance issue and to stop boarding while we worked through things. I returned to the flight deck to grab my vest and go outside and immediately had a supervisor behind me asking what was going on. We explained to her and she made some comment about the number of connections we had and we needed to get out on time. I conducted the walk around and returned to the flight deck for preflight preparation. We had a deice personnel come to the flight deck and began coordinating clearing the underside of the flaps and a deice plan at the gate. Meanwhile the captain had cleared the Stall Warning issue with Maintenance Control as it was connected to having the flaps down; and boarding resumed. As we continued to prepare the flight deck and post deice for the underside of the wings; we had finally gotten a mechanic onboard to come and clear the flaps once deicing was complete prior to anti-ice application to get the Maintenance Release. In the meantime; the ATIS and FICON (Field Conditions) were not clear on the field codes. The captain was working with dispatch and I was trying different takeoff data to get legal numbers. Finally; Maintenance Release on board; the gates were closing the door and we were starting the deice process around 30-40 minutes late. We were almost complete the 40 minute process and we believe that the de-icer got anti ice fluid into the APU; causing a shut down. We began coordinating with Maintenance Control and station to bring the bridge back as the aircraft was without power. Station refused to bring the bridge back and had them reapply ground power. Station and Station Maintenance asked us to attempt a restart the APU. We asked station to ask the maintenance technician how much anti ice was in inlet; as this was going to affect our risk tolerance for attempting a restart. We were told it was just a couple drips. We attempted a restart and within two minutes of stabilizing the APU shut down again. At this point we refused the aircraft as we were not going to accept a deferral for an APU in a blizzard. At this point we asked for the bridge back. The bridge had to retract the external power to move so we went completely cold and dark to preserve the battery. The flight attendants were unable to disarm doors IAW (In Accordance With) there because that is the only means of egress. When the agent brought the bridge; she immediately began to open the door requiring swift intervention to prevent inadvertently slide deployment. This created an intense few moments for the crew while we got the door disarmed safely. Finally; the agent took off and we did not open for almost another 10 minutes. We egress and were continually delayed as one jet bridge was downed; so the ground team had to move aircraft around to board and get other flights out. All in all we closed 7.5 hours late. This included an intense mental strain with driving to the airport; trying to get an aircraft out in a blizzard and finally a near slide deployment. As we landed in ZZZ1; I was exhausted. I was missing radio calls and switches on ground. I was irritable with my captain. I was not fit to continue. I did not feel safe to even be an ABP (Able-bodied Passenger) on DH (Dead Head). Our flight to ZZZ2 was getting delayed by an hour and weather in ZZZ2 was only going to deteriorate. I called fatigued and asked for a hotel for a report time at or after XD:00 the next day to get a full circadian night sleep before continuing to work. I was just released from all duty.