Sleeping at Terminal 2 in Beijing airport

I will arrive at Terminal 2 around 1AM and I'm considering to stay at the airport and wait for the first train in the morning, is this doable? I am a solo traveler. Is there any place in T2 where I can rest for a while? I read that the shower areas are in T3, is it possible for me to go to T3 and stay there instead? Will the airport staff let me in? Thank you.