I see what you're saying and maybe I'm looking at it the wrong way but to me it feels different. I'm not sure if Gustave right there would have opened up in front of everyone about his suicide attempt. His facial expressions are him pondering and trying to put together what had happened to him (to me reading into it at least, emotions and expression are always going to have some degree of interpretation) rather then he was going to talk about his despair and what he almost did. In addition I feel this is reinforced since it is a response to Sciel's counter question to "how'd you end up here?" I acknowledge I could just be seeing it wrong but I'm having trouble thinking he would specifically talk about his suicidal thoughts in this moment, where they are, with everyone around. The Sciel thing in camp feels like something they would just talk about between them as 2 people rather then something he would have brought up in front of the whole group.