Did I Miss Something?

[Potterfanme]

No: HPFGUIDX 81169

I am reading COS (my new UK edition) and something doesn't make sense 
to me.  If this has been discussed just tell me the post number 
please.

When Harry is in the hospital ward having his bones regrown and they 
bring Colin Creevey in, McGonagall gets Madam Pomfrey.  When Pomfrey 
asks what happened, Dumbledore says that Minerva found him on the 
stairs.  A few lines down, McGonagall says that she shudders to 
think...if Albus hadn't been on the way downstairs for hot chocolate, 
who knows what might have....

Ok what did I miss?  If McGonagall found him, what does that have to 
do with Albus getting hot chocolate?  Did she see something else and 
Albus came along and saved her?  I just don't understand.
Help!
Susan who is shaking her head thinking she is totally daft