Elaine Lau Wan-ling, 30, is a Hong Kong nurse who spent six months with MSF in southern Sudan in 1999, six months in Kosovo in 2000 and seven months in Herat, Afghanistan in 2001-2. This is her story:

'The most difficult place was Sudan, in a rebel-controlled area. There were no military or police - you were responsible for your own security. The feeding-centre supervisor lost an eye in a shooting. We had security training with MSF about carrying radios and about how important it is to know which direction to go if you're evacuated, and always to carry the phone numbers of local staff because they know the bush so well. They helped us hide for two days - that was frightening. In Herat, it was relatively stable because the area had a strong commander. MSF doesn't allow women volunteers to walk on the streets there, especially before the war in Iraq when NGOs [non-governmental organisations] were being threatened and people were anti-American and anti-foreigner.

'I worry about getting kidnapped. You think about it and if you're a woman, you think about rape - it's not only about being locked in a room - so the fear is stronger. It's part of the psychological preparation you try to do: once you choose to work in an unstable country, you might be in that danger. I have a feeling Arjan is alive - we all have hope.