Belarus does not have its own nuclear weapons - so any retaliatory strike from the UAF does not need to observe the border. The rail bridges and yards connecting Belarus and Ukraine are the obvious target.

I've read that there's been some resistance to Lukashenko shown by rail workers (small acts of sabotage) - which might be worth bearing in mind if/when strikes are scheduled.

Whoever brought down those spans on the Kerch bridge clearly timed their action to minimize casualties (something that makes me think it was a Ukrainian action - essentially the opposite of randomly destroying civilian-only targets).

Just a non-military person looking at a map and considering what's probably obvious to folks with mil backgrounds...