It has been a while since I watched Breaking Bad so there's a detail that I don't recall concerning the bomb that Walt planted in the nursing home... weren't there any surveillance cameras in the nursing home? I am thinking that since Hector Salamanca was no more a person of interest to the DEA he wasn't being watched by them... But I mean shouldn't the nursing home have surveillance cameras? If yes, how did Walt manage to escape with that?
Well, If I am not mistaken there is a scene where Walt is hiding just outside the window to Salamanca's, which means that is his likely means of ingress as he certainly climbed out the window to hide. This method doesn't risk him being spotted with the exception of any external surveillance, which he very likely cased out beforehand in preparation for his plan and evaded.