Cristal says “ANAGRAM” and plays her A - A

If Darren has any of N, G, R or M, he would have to choose amongst them and play one. Of those he only has the G so he plays it - AG

Cristal plays her R - AGR

Darren has no A or N, splays his I and says “AGRICULTURE” - AGRI

Cristal has no C, so plays an N to the end and says “CHAGRIN”, hoping Darren doesn’t have an H - AGRIN

Darren does have an H - HAGRIN

Cristal doesn’t have a C, and can’t think of anything else so she picks up HAGRIN and puts them in fer face down, negative pile, much to her chagrin.