Having seen too many of these type of incidents recently, my attitude to the traditional sim 'let the PM initiate the UA and the PF recover' has changed. I now initiate the UA sequence with the APs off and challenge the PF to remain adequately stabilised for 10 seconds before switching the APs back on. Some guys almost immediately enter their own UA.If they are good, I will ask them to look at the AP panel for 10 seconds or close their eyes until it occurs. Then ask the PM to reselect both APs and the PF can recover. I also repeat the ex in SAS mode without ATT to recover. Everyone forgets to use their feet! This tends to remind crews of the importance of a quick scan and quick crew actions to get the APs back ASAP after getting it 'back in the ballpark'.
Switching off the gang bar in IMC is tantamount to attempted suicide. No SAS, no instruments, no ICS, no AWG, no chance. AHRS can take up to 60 seconds to realign and considering the rates of likely pilot input, probably longer.