I am going to base this on stereotypical manner, being boy is naturally bigger, handyman and buffer and girls being smart,witty and flexible. some strengths of joaquin it he could use his strength, or he could use his handy skills to escape, christina could use her smarts to analyze her position and plan a way to get out
(i couldnt give better answers since you didnt specify the box or anything)
sorry. hope i could help.