Mine refuses to use ipmi. Also all switches use the same password.

machine had a RW optical drive

Ah, the Private Manning protocol.

I dunno, gluing usb's in a super sensitive environment like that is actually logical; on the disc drives - they could disable autoplay as well though removing or gluing them closed would be preferable. USB is just such an easy attack vector where the individual plugging it in may not have skills themselves - it might be easier to bribe cleaning folks for example - or inject a person into a cleaning team. Ideally they would attack multiple nodes of your target's network via as many avenues as possible; which makes the network and vpn thing just silly indeed; perhaps they were waiting for someone to try something with excellent infosec / firewalls / traffic shaping. yeeeeah lol.

I'm sure there are more elegant ways they could have disabled the USB ports, but this might have been partially to avoid users being able to accidentally compromise their device by sticking a thumb drive they found in the parking lot in to see what was on it. For exfiltration and VPN usage over the network there are other controls they can/likely had put in place that you may just not have known about